The goal of phonological treatment is to improve the skills of children with phonological disorders of speech, yet data to support the efficacy of treatment is limited due to the slow nature of phonological development and the lack of adequate measures to assess small increments of change during therapy. The proposed investigation presents a new measure that offers potential for the assessment of incremental change, the Scaffolding Scale of Stimulability (SSS) (Glaspey, 2002). The SSS is a dynamic assessment that measures expressive phonology based on the types of cues and modeling a child needs to produce targets within increasingly complex linguistic environments. The aims of the proposed investigation include: (1) assessment of the validity and reliability of the SSS; (2) comparison of outcomes of the SSS with static assessment measures; and (3) documentation of treatment effects during six months of cycles treatment. Overall, the proposed investigation will provide insight into the nature of phonological change, which will allow for better measurement of treatment efficacy in future studies. [unreadable] [unreadable]